The 28-year-old has been training with the club and played in the Development League game against Hearts at Tannadice.
The Scottish Sun report that manager Ray McKinnon is looking to bolster his defensive options in United's bid to win promotion back to the Premiership.
He said: "Francois looks really good. He's a left centre-back and is a big lad who's decent on the ball for his size. He's actually a bit like his brother and has been great in his approach to everything since arriving. We'll let him go home at some point this week and then re-evaluate things after that."